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Zielflug [23.3K]
3 years ago
13

Find S7 for the geometric series 2 + -6 + 18 + -54 +…

Mathematics
1 answer:
nikitadnepr [17]3 years ago
8 0

Answer:

  1094

Step-by-step explanation:

The sum of terms of a geometric series is given by ...

  Sn = a1·(r^n -1)/(r -1)

You want the sum for ...

  a1 = 2, r = -3, n = 7

Filling in the numbers, we get ...

  S7 = 2·((-3)^7 -1)/(-3-1) = 2(-2188)/(-4)

  S7 = 1094

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Twenty years​ ago, 51​% of parents of children in high school felt it was a serious problem that high school students were not b
Anit [1.1K]

Answer:

Step-by-step explanation:

We would set up the hypothesis test.

For the null hypothesis,

p = 51/100 = 0.51

For the alternative hypothesis,

P ≠ 0.51

Considering the population proportion, probability of success, p = 0.51

q = probability of failure = 1 - p

q = 1 - 0.51 = 0.49

Considering the sample,

Sample proportion, P = x/n

Where

x = number of success = 278

n = number of samples = 800

P = 278/800 = 0.35

We would determine the test statistic which is the z score

z = (P - p)/√pq/n

z = (0.35 - 0.51)/√(0.51 × 0.49)/800 = - 9.05

Recall, population proportion, P = 0.45

The difference between sample proportion and population proportion(p - P) is 0.51 - 0.35 = 0.16

Since the curve is symmetrical and it is a two tailed test, the p for the left tail is 0.51 - 0.16 = 0.35

the p for the right tail is 0.51 + 0.16 = 0.67

These proportions are lower and higher than the null proportion. Thus, they are evidence in favour of the alternative hypothesis. We will look at the area in both tails. Since it is showing in one tail only, we would double the area

From the normal distribution table, the area below the test z score in the left tail is < 0.00001

We would double this area to include the area in the right tail of z = 9.05 Thus

p < 0.00001 × 2

p < 0.00002

Since alpha, 0.01 > than the p value, then we would reject the null hypothesis.

Therefore, at 5% significance level, we can conclude that parents feel differently today than they did twenty years​ ago.

7 0
3 years ago
PLEASE HELP!!! Find the distance between the following two points: (3,7) and (5,0). Round to the nearest TENTH.
snow_lady [41]

Step-by-step explanation:

7.3 when rounded to the nearest tenth

5 0
3 years ago
Heloïse considered two types of printers for her office. Each printer needs some time to warm up before it starts printing at a
slava [35]

Answer:

1) a, the first printer

2) b, the second printer

Step-by-step explanation:

7 0
3 years ago
6(2x + 4) = 3(4x + 8)<br> Please answer this!
Ahat [919]

Answer:

Infinitely many solutions

Step-by-step explanation:

6(2x + 4) = 3(4x + 8)

Distribute the 6

6 * 2x = 12x and 6 * 4 = 24

12x + 24 = 3(4x+8)

Distribute the 3

3 * 4x = 12x and 3 * 4 = 24

12x + 24 = 12x + 24

On both sides of the equal sign we have 12x + 24.

When both sides are equal there are infinitely many solutions.

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Sherry was in charge of distributing 25 food items
Valentin [98]

Answer:

? i dont think you finished the sentence

Step-by-step explanation:

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